<?php
header('Content-type:text/html;charset=utf-8');
    $username = isset($_POST['name-register']) ? $_POST['name-register'] : '';
    $password = isset($_POST['password-register']) ? $_POST['password-register'] : '';
    $link = mysqli_connect('localhost', 'root', '123', 'Dress', '3306');
    if($_POST["register"]) {
    if ($username == "" || $password == "" ) {
        echo "<script>alert('请确认信息完整性！'); history.go(-1);</script>";
    }
    else {
        $sql = "select username from user where username = '$username'"; //SQL语句
        $result = mysqli_query($link,$sql);    //执行SQL语句
        $num = mysqli_num_rows($result); //统计执行结果影响的行数
        if ($num)    //如果已经存在该用户
        {
            echo "<script>alert('用户名已存在'); history.go(-1); </script>";
        } else    //不存在当前注册用户名称
        {
            $sql_insert = "insert into user (username,password) values('$username','$password')";
            $res_insert = mysqli_query($link,$sql_insert);
            //$num_insert = mysql_num_rows($res_insert);
            if ($res_insert) {
                echo "<script>alert('注册成功！'); history.go(-1);</script>";
            } else {
                echo "<script>alert('系统繁忙，请稍候！');history.go(-1); </script>";
            }

        }

    }
}
?>